Pressure and temperature: how they affect flavor? - Page 2

[LeoZ]

Illy hypothesizes, and then refers to an experiment that would seem to validate the hypothesis, that pressure in excess of ~9 bar causes the fines to migrate towards the filter, where they create a sort of impenetrable barrier. He has some pictures representing computer-generated models of the puck's "time-dependent geometry".

I have been thinking about the effects of pressure in connection with the magneto-piston we were discussing over in the lunatic fringe of the Peppina Marries MiniGaggia thread. Gedankenespresso is the tastiest brew. After a hand-controlled preinfusion, pressure created by a magneto-piston would start off high (as the repelling magnets are closest together) and then, instead of ramping up, fall off exponentially, say from 11 bar to 7 bar. I am wondering how that profile would affect migration of fines and the flavor.

Regards
Timo

this is odd, especially since italians are proponents of the fine grind/high pressure method. arent they?

my giotto came set at 11bar from the factory, and im sure most other european machines are the same. is illy the maniacal outcast of italian espresso culture? lol

[cannonfodder]

last i checked the cost was what? 2 g's? heh... i dont want to get kicked out of the house just yet!

I believe I saw something on the order of 8G's...

Right off Versalabs m3x page...

The M3x comes complete with a Dell laptop computer running Windows XP and a control program written in Labview 8. Labview is the process software used to launch rockets, operate distilleries and refineries, you name it. A very reliable package with 20 years of development and enormous industrial following.

Dimensions - 16" deep x 14" high x 9" wide

Weight approximately 70 lbs.

Target price $8000

[LeoZ]

oh, i meant their 'regular' grinder

[cannonfodder]

Sorry, that is for their espresso machine.

[timo888]

...italians are proponents of the fine grind/high pressure method. arent they?

my giotto came set at 11bar from the factory, and im sure most other european machines are the same. is illy the maniacal outcast of italian espresso culture? lol

Illy gives 9 ±2 bar as the acceptable range for inlet water pressure. Not too maniacal there

In the section on "cake shape" (8.5.4) Illy discusses basket size, specifically the ratio of height to diameter, remarking that when the height of the basket exceeds one-fifth the width of the basket, "excessively high pressure" is required for optimal extraction.

Illy doesn't mention what the dimensions were for the cake of the "porous, deformable medium" in the experiments which showed that pressure in excess of 9 bar resulted in decreased flow of the "fluid".

What's the Giotto's basket size, btw?

Regards
Timo

P.S. It would be a convenience to have in one place a listing of machines, and their basket dimensions.

[LeoZ]

Illy gives 9 ±2 bar as the acceptable range for inlet water pressure. Not too maniacal there

In the section on "cake shape" (8.5.4) Illy discusses basket size, specifically the ratio of height to diameter, remarking that when the height of the basket exceeds one-fifth the width of the basket, "excessively high pressure" is required for optimal extraction.

Illy doesn't mention what the dimensions were for the cake of the "porous, deformable medium" in the experiments which showed that pressure in excess of 9 bar resulted in decreased flow of the "fluid".

What's the Giotto's basket size, btw?

Regards
Timo

P.S. It would be a convenience to have in one place a listing of machines, and their basket dimensions.

my non calibrated dial caliper has these giotto measurements:
double basket
width (at top): 2.316" - 58.8mm
width (at bottom): 1.93" - 49.022
height: 0.982" - 24.9mm

since this more than doubles their recommendations, illy either means a single basket, or the giotto should be running at 11bar. lol

going by the single basket:
width (at top): 2.316" - 58.8mm
width (at bottom): 1.4" - 35.56mm
height: .807" - 20.49mm

this is still a bit more than their recommendations. so.. now what? lol if 11bar means high pressure, it doesnt work, way too bitter!

[timo888]

...illy either means a single basket, or the giotto should be running at 11bar. lol

I too think Illy must mean the single basket, though here's what is written:

The double dose filter is a cylinder, around 12mm height and 60 mm width, the precise dimensions depending on the machine.

When you get bitterness in the cup, how do you know it is not to be ascribed to water-temperature?

On the Giotto, are you able to set the temperature at the puck to the low end of the range, i.e. to 85°C?

Regards
Timo

[LeoZ]

When you get bitterness in the cup, how do you know it is not to be ascribed to water-temperature?

On the Giotto, are you able to set the temperature at the puck to the low end of the range, i.e. to 85°C?

Regards
Timo

12mm x 60mm? how can 17grams of grounds fitting into that? anyone good at volume and conversion calcs? :p

the giotto has a HX, so temp is set by flushing. ive flushed from 1oz to 8oz..

[timo888]

12mm x 60mm? how can 17grams of grounds fitting into that? anyone good at volume and conversion calcs? :p

the giotto has a HX, so temp is set by flushing. ive flushed from 1oz to 8oz..

Right, I think there's a typo, and Illy means the single basket not the double. However, you have in mind the contemporary dose whereas Illy has a smaller classical dose in mind. For the single shot, llly gives 6.5 ± 1.5g. So the extremes for the Illy doppio dose are as little as 10g and as much as 16g.

In my experimentation with Peppina and the Cremina, I find bitterness the result of high temperature. I cannot adjust the pressure on the Peppina but can do so on the Cremina. With the Cremina, and water on the cool side (e.g. the first shot) I can exert quite a lot of pressure on the lever and not encounter bitterness. But if the water temperature is too hot, it doesn't matter how little pressure I place on the lever, the shots tend towards the bitter.

I hope you're using that HX flushing water to irrigate a few hectares
Regards
Timo

[LeoZ]

I hope you're using that HX flushing water to irrigate a few hectares
Regards
Timo

you were worried i was running too hot, i was only trying to prove a point!

actually i tend to flush around 2oz, but when shots are within 5mins, i dont seem to need to flush at all, esp with the lower pressure im running, which was my original question.. and now im only more confused, but have learned so much more!